Human Parasites

About Human Parasites


Human parasites are organisms that live inside us so that we become their hosts. Since these parasites are unable to produce food for themselves, they depend on us for their survival. Unfortunately, parasites harm human beings because they consume our food and nutrients, they can destroy our tissues and cells, and they produce toxic waste products that can make people very ill.

In some underdeveloped countries, human parasite infections are epidemic, sickening and killing thousands upon thousands of people each year. In America, parasitic infections are not as widespread, but these infections are on the rise for various reasons. For example, people bring parasites with them when they immigrate to the U.S., and soldiers often return to the U.S. bringing parasites with them from overseas. In addition, our way of life can contribute to the spread of parasites. A large percentage of children contract parasites from their day care centers. Children and adults with dogs and cats at home are at risk for getting parasites. Also, those people that eat at restaurants are at a higher risk because food handlers have been known to spread parasites.

It is estimated that about 50% of the U.S. population is infected with at least one type of parasite. Not all these people have symptoms; only about 25% of these individuals have active infections that are producing symptoms. Certain parts of the United States have a higher incidence of human parasite infections. This is true for areas that tend to be warmer and more humid. Also, some occupations put people at a higher risk of infection. These include electrical workers, plumbers, animal handlers, soldiers who travel abroad, gardeners, and sanitation workers.

Human parasites are just about everywhere in our environment, so it is easy to become infected. The following is just some of the ways people can acquire parasites:

• insect bites

• animal feces

• walking barefoot

• handling raw meat and fish

• eating raw or undercooked pork, beef or fish

• handling soiled litter pans (cats)

• eating contaminated raw fruits and vegetables

• eating meals prepared by infected food handlers

• drinking contaminated water

• having contact with infected persons (including sexual contact, kissing, and shaking hands)

• inhaling contaminated dust (parasitic eggs or cysts)

types of human parasites

Human parasites consist of tiny protozoa and amoebae which can only be seen under a microscope, and parasitic worms and flukes, which are larger. The small protozoa and amoebae are spread to people by air, water, food, insects, animals, and human contact. Parasitic worms are usually acquired when one ingests contaminated meat.

It is the small human parasites that pose the greatest risk to our health. These tiny protozoa and amoebae can travel from the intestines to the bloodstream, muscles, and vital organs where they can impose considerable damage on their hosts. In their resting stage or cyst stage, these parasites are very infectious. They are very small and light, so they can float in the air and become inhaled. The parasites have been linked to cancer, rheumatoid disease, asthma, diabetes, multiple sclerosis, pyorrhea, and other diseases.

Below, we will take a closer look at some of the common parasites that can infect humans:



Pinworms (enterobius follicularis) – This is one of the most common human parasites in the U.S. This worm makes its home in the host’s colon, but it lays eggs outside of the host’s body. Transmission can occur through unclean hands, clothes, and bed sheets.

Symptoms: irritation and scratching in the anal area.

Hookworms (necator americanus) – This is an intestinal human parasite that begins it’s life outside of the body, in soil or water, where humans become infected. We can drink water that contains hookworm larvae, or we can ingest contaminated fruits and vegetables. This worm attaches itself to the human intestines where it drinks blood (this worm actually has teeth!).

Symptoms: weakness, abdominal pain, nausea, diarrhea, anemia.

Roundworms(ascaris lumbricoides) – One of the most common human parasites in the entire world, these worms are as large as a writing pencil. People are infected by ingesting the eggs which can be in the soil, fruits, and vegetables. The eggs find their way from the intestines to various organs where the can cause severe damage.

Symptoms: Weight loss, weakness, infection, abdominal pain.

Tapeworms (taenia solium, diphyllobothrium latum, and taenia saginata) – Common in dogs and cats but rare in humans. To become infected with this parasite, one must swallow fleas that are infected with tapeworm larvae. This worm can take-up residence in the intestines where it will steal valuable nutrients and expel dangerous waste. The human host infected with this worm may not show any symptoms.

Symptoms: mineral imbalance, bloating and gas, dizziness, hunger pains, “fuzzy” thinking, digestive problems, sensitivity to touch, and allergies.

Liver Fluke (clonorchis sinensis) - A flat worm that attacks the host’s liver by causing inflammation and making holes. It can survive inside a human host for approximately 30 years. Humans acquire this parasite through eating undercooked fish, contaminated vegetables, human feces used as fertilizer, or by drinking (or swimming) in contaminated water.

Symptoms: an enlarged liver, pain in the right side of the body, depression, edema, vertigo, bile stones, and cancer.



Giardia lamblia – After pinworm, this is the most common parasitic infection in the U.S. , with several million cases occuring annually. Giardia resides in the intestine (or gall bladder) of it’s host and is spread by fecal contamination and through water. Poor sanitation and unsafe sexual practices contribute to the spread of this parasite. Since it is resistant to chlorination, Giardia can be found in tap water, but it can be found in natural streams as well.

Symptoms: abdominal pain, food sensitivity, vitamin deficiency, diarrhea.

Entamoeba histolytica – This one-celled organism produces a disease called amebiasis. It can be found in water and damp environments, in soil, and it can contaminate fruits and vegetables. This protozoan spreads through fecal contamination. Poor sanitation contributes to infection, unsafe sexual practices, and it can spread through crops that are fertilized with human waste. Although most people with E. histolytica don’t have symptoms, this parasites is the leading cause of death by protozoa after malaria.

Symptoms: abdominal pain, weight loss, weakness, diarrhea.

Cryptosporidium – A single celled parasite that can infect the digestive tract, causing serious gastrointestinal problems. Once again, this parasite is spread when something has come in contact with feces, then finds its way to a person’s mouth. Cryptosporidium can be widely found in the outdoors. It can contaminate public water supplies, and lakes and streams. It can also be spread by food handlers who work in restaurants, as well as child daycare workers. Unsafe sexual practice is another way it can be spread.

Symptoms: stomach pain, diarrhea, “fluish” syptoms.

Toxoplasma gondii - a common, crescent shaped parasite that invades the central nervous system. Humans become infected with this organism by eating undercooked meat or by handling infected cat litter, which can contain eggs. Most people have been exposed to this parasite and show antibodies for it, but only few individuals show symptoms. Those with a compromised immune system are more susceptible.

Symptoms: “fluish” symptoms, fever, chills, fatique, headache.

symptoms of human parasite infections


human parasite infections are difficult to diagnose because many exhibit only vague symptoms, or no symptoms at all. The following symptoms, however, may indicate human parasite infection:

• Diarrhea with foul-smelling stool that becomes worse in the later part of the day

• Sudden changes in bowel habits (e.g. constipation that is now soft and watery stool)

• Constant rumbling and gurgling in the stomach area unrelated to hunger or eating

• Heartburn or chest pain

• Flulike symptoms such as coughing, fever, and nasal congestion

Food allergy

• Itching around the nose, ears, and anus, especially at night

• Loss of weight with constant hunger

• Anemia

• Anxiety caused by the metabolic waste products of the parasites

Other symptoms of human parasite infections include anemia, blood in the stool, bloating, diarrhea, gas, loss of appetite, intestinal obstruction, nausea, vomiting, sore mouth and gums, excessive nose picking, grinding teeth at night, chronic fatigue, headaches, muscle aches and pains, shortness of breath, skin rashes, depression, and memory loss .

diagnosis of human parasite infections


The conventional method of laboratory analysis has been the use of a microscope to analyze stool specimens for human parasites, eggs, or their cysts. This has resulted in a high failure rate of identification. Dr. Skye Weintraub, N.D.,has written an excellent book on parasites (The Parasite Menace, 2000); he recommends you consider the following factors when attempting to achieve a more accurate identification of parasites:

• Choose a lab that analyzes parasites as their specialty

• Make sure they analyze multiple stool specimens instead of just one

• Choose the rectal swab technique which analyzes mucus instead of stool

• Choose a lab that uses a fluorescent stain; this makes identification more accurate

• Consider immunoassay test for the identification of parasites, which detects antibodies and is not dependent on stool samples

• For detecting parasites outside of the intestinal tract, consider the following blood tests: indirect hemagglutination test; ELISA assay; latex agglutination; and counter-immuno-electro-phoresis

treatment of human parasites

Alternative Treatment

Dr. Hulda Clark, Ph.D., N.D. (The Cure for all Diseases, 1995) has done extensive work in the field of human parasites. She recommends the following protocol for natural parasite cleansing:

• Black walnut hull tincture extra strength

• Wormwood capsules (containing 200-300 mg)

• Cloves – these must be fresh ground & should be about 500 mg. You can sometimes find these already prepared and encapsulated

I recommend that you check Dr. Clark’s book for the exact parasite cleanse schedule she recommends. There is also a separate maintenance schedule that she has published as well.

Nutritional guidelines

The following dietary changes may help prevent or treat parasites in humans:

• Eat a well-balanced diet with lots of fiber, vegetables, fruits, whole grains, nuts, and seeds. Fiber helps eliminate worms from the intestines; good nutrition improves immune function and protect the body against parasitic invasion

• Limit dairy foods, sugar, and fat. Parasites thrive on these foods

• Avoid eating raw or undercooked fish, pork, or beef

• Take daily multivitamin/mineral supplement to prevent malnutrition and improve immune function

• Supplement diet with probiotics such as Lactobacillus acidophilus, Bifidobacteria, and other beneficial intestinal bacteria that cultivate normal intestinal flora and suppress the spreading of parasites

Conventional treatment of human parasites

Traditional medical treatment for parasites typically involves a prescription for antiparasitic drugs. Doctors will look at the severity of the infection and the type of parasite(s) involoved before prescribing one or more of the following drugs:

• Albendazole

• Furazolidone

• Iodoquinol

• Mebendazole

• Metrodidazole

• Niclosamide

• Paromomycin

• Pyrantel pamoate

• Pyrimethamine

• Quinacrine

• Sulfadiazine

• thiabendazole

It is recommended that precautions be taken so that you are not reinfected with parasites. For example, when one family member is treated for parasites, all other family members should be treated as well. Family members should keep their hands clean, as well as clothes, bed sheets, and even toys.

Prevention of parasites

The following measures can help prevent parasitic infections:

• Wash hands before eating and after using the restroom

• Wear gloves when gardening or working with soil or sand because soil can be contaminated with eggs or cysts of parasites

• Pregnant women should avoid handling cat litter

• Do not allow children to be licked or kissed by pets that are not dewormed regularly

• Wash fresh vegetables carefully. Many people get Entamoeba histolytica by eating contaminated raw fruit and vegetables

• Avoid eating raw meat, which may contain Giardia lamblia

• Wear long-sleeved shirts, long pants, and boots when walking in the woods. In addition, spray insect-repellent on clothing to prevent tick bites


Byfield, Mike. “It’s spring—don’t drink from the Tap!” Newsmagazine (BC Edition). Vol. 29, Issue 10, 2002.

Clark, Hulda. The Cure for all Diseases. Chula Vista, CA: New Century Press, 1995.

Galland, Leo. “Colonies Within: allergies from intestinal parasites.” Total Health. Volume 21, no. 2, 1999.

Kroeger, Hanna. Parasites: The Enemy Within. Hana Kroeger Publications, 1991.

Kucik, C., Corry, J., Martin, G. L., & Sortor, B. “Common Intestinal Parasites.” American Family Physician. Vol. 69, Issue 5, 2004.

Weintraub, Skye. The Parasite Menace. Pleasant Grove, UT: Woodland Publishing, 2000.